class Named{
    name: string;
}
class Person{
    name: string;
}
let pn: Named;
pn = new Person();  // 结构相同，可以赋值

let funcx = (a: number)=>0;
let funcy = (a: number, b: string)=>0;

funcy = funcx;  // Ok
// funcx = funcy; // Error

let rtnx = ()=>({name:"zha",});
let rtny = ()=>({name:"dao", addr: "sz"});

rtnx = rtny;    // Ok
//rtny = rtnx;    // Error







